A113782 a(n) = k such that A083087(k-1) = n.

1, 3, 2, 6, 5, 10, 15, 4, 21, 9, 28, 36, 8, 45, 14, 55, 20, 66, 78, 7, 91, 27, 105, 120, 13, 136, 35, 153, 44, 171, 190, 12, 210, 54, 231, 253, 19, 276, 65, 300, 325, 26, 351, 77, 378, 90, 406, 435, 11, 465, 104, 496, 528, 34, 561, 119, 595, 135, 630, 666, 18, 703